Differential type driving wheels system

ABSTRACT

Two webbed driving wheels are rigidly secured at both ends of a rotating live axle, which axle, through a system of pullies and belt and a torque-converter, receives the rotating power generated by a motor. The webs of the driving wheels are made of resilient or flexible material and a certain number of these webs are in constant frictional engagement with two pairs of driven wheels. The power generated by the motor is transmitted to the driven wheels by the driving wheels and this, due to the frictional contact existing between them. When negociating curves the resilient webs of the driving wheels act as a differential system.

United States Patent [191 Lacroix DIFFERENTIAL TYPE DRIVING WHEELSSYSTEM [76] Inventor: Jean Paul Lacroix, 12064 Taylor Blvd., Montreal,Quebec, Canada 22 Filed: Jan. 27, 1972 21 Appl. No.: 221,348

[52] US. Cl. 180/74, 180/76 [51] Int. Cl B60k 23/00 [58] Field of Search180/74, 76

[56] References Cited UNITED STATES PATENTS 3,446,302 5/l969 Schoonover180/74 X 3,447,622 6/1969 Ovshinsky et al 180/74 X Jan. 29 1974 PrimaryExaminer-Richard E. Aegerter Assistant Examiner-H. S. Lane [5 7]ABSTRACT Two webbed driving wheels are rigidly secured at both ends of arotating live axle, which axle, through a system of pullies and belt anda torque-converter, 'receives the rotating power generated by a motor.The webs of the driving wheels are made of resilient or flexiblematerial and a certain number of these webs are in constant frictionalengagement with two pairs of driven wheels. The power generated by themotor is transmitted to the driven wheels by the driving wheels andthis, due to the frictional contact existing between them. Whennegociating curves the resilient webs of the driving wheels act as adifferential system.

9 Claims, 5 Drawing Figures SHEET 2 OF 2 WHEN? 1 DIFFERENTIAL TYPEDRIVING WHEELS SYSTEM The invention relates to a transmission systemapplied to any types of self-propelled vehicles, the propelling wheelsof which are on stationary axles in relation to the body of the vehicle,such as all terrain vehicles, garden or farm tractors earth movingmachinery, graders, lumbering machinery or the like.

More particularly, the invention relates to a unique axle differentialtype driving wheels system, for providing the frictional driving of allterrain type vehicles. This system replaces the complex and costlydifferentials and multiple live axles shafts existing in such vehiclesby only one live axle, and yet, permits the retaining of fulldifferential movement in propulsion for each and every one of the fourdriven wheels, with the additional individual advantage of limited slip.

In the existing vehicles wherein there are the provision of frictionaldriving wheels disposed between two pairs of driven wheels for thepurpose of driving the latter or for the purpose of transferring thepower from one set of driving wheels to an adjacent set of nondrivingwheels, or for improving the traction of the vehicle when the conditionof the road so requires, there are the provision of bearings, universaljoints, differentials housings, chains, chain tensioners, chainhousings, sprocket-wheels, differential gears and gear boxes, hydraulicor air power support, all these complicating the system andnecessitating more constant and frequent maintenance such as greasing,oiling, etc.

The invention consists of two webbed driving wheels rigidly secured atboth ends of a rotating live axle, which axle, through a system ofpullies and belt and a torque-converter, receives the rotating powergenerated by a motor. The webs of the driving wheels are made ofresilient or flexible material and a certain number of these webs are inconstant frictional engagement with two pairs of driven wheels. Thepower generated by the motor is transmitted to the driven wheels by thedriving wheels and this, due to the frictional contact existing betweenthem. When negociating curves the resilient webs of the driving wheelsact as a differential system.

One object of the present invention is the provision of a driving systemwhich through its extreme simplification minimizes both the weight andthe cost of the vehicles so equiped.

Another object of the invention is the provision of a driving system,which through the simplicity of its design makes field repairs not onlypossible but also fast and easy, and possibly a one mans job, even onheavy machinery, by permitting a damaged part to be replaced fromoutside by merely slipping a spare one in, with the removal of only onenut.

A further object of 'the'invention is the provision of a driving systemwhich, through the simplicity of its design avoids the complexity, highfabrication cost, high maintenance cost, of multiple live axles,universal joints, gear differentials, differential boxes, chains, chaintensioners, chain housings, sprocket-wheels, etc. In fact all theseitems are replaced by a unique live axle provided with two webbeddriving wheels at its extremities.

The foregoing and other features and advantages will become moreapparent from the following description having references to theappended drawings wherein:

FIG. 1 is a perspective view of a unique live axle and of twodifferential type driving wheels according to the invention shownmounted in frictional engagement with two pairs of driven wheels on anall terrain vehicle;

FIG. 2 is a side view of one of the differential type driving wheelsaccording to the invention, partially cutway, showing the way thedriving wheel engages the driven wheels for the purpose of driving thevehicle;

FIG. 3 is a side view of a driving wheel according to the invention,partially cut-way, showing the form of the wheel and the parts it iscomposed of;

FIG. 4 is a second embodiment of a driving wheel according to theinvention; and

FIG. 5 is a further embodiment of a driving wheel according to theinvention.

Referring now to the drawings, FIG. 1 shows two driving wheels 1 rigidlyfixed at both ends of a live axle 3, which axle may be connected to theframe of the vehicle or may be supported by any conventional means (notshown).

Each wheel 1 is in frictional engagement with a pair of driven wheels 5.There is one pair of such wheels 5 at each side of the vehicle. A rightside wheel 5 and a left side wheel 5 are rotatably mounted at both endsof a dead or stationary axle or shaft 7. Each wheel 5 freely rotatesaround the dead axle in a conventional manner.

By driven wheels 5 it must be understood the wheels which, when drivenby a driving mechanism, such as the driving wheels 1 in the presentcase, provides the propelling or moving of the vehicle.

It is to be noted that the driven wheels 5 are not the steering ordirection wheels of the vehicle. In fact, the vehicle is provided withfront wheels (not shown) for steering purposes.

Driven wheels 5 are provided with ribs 8 for facilitating theirfrictional engagement with the driving wheels 1 as will be explainedlater.

A motor 9, of conventional type, fixed to the frame of the vehicletransmits power, through a system of pullies 1 1 and belt 13, and atorque-converter (not shown) to axle 3 and therefore to driving wheels1.

The power is then transmitted tothe periphery of driven wheels 5 bymeans .of the frictional engagement of wheels 1 with the wheels 5 aswill be explained in latter paragraphs.

FIGS. 3, 4 and 5 show three embodiments of driving wheels 1 that may beused in the invention for obtain: ing the desired results.

FIG. 3 shows a wheel l made of a metal sleeve 15, over which is rigidlysecured an annularly shaped resilient part 17. The resilient part isprovided with webs 19 formed integrally thereof and radially projectingtherefrom. Any other adequate ways of connecting the webs to theannularly shaped resilient part may also be used.

In this kind of driving wheel the metal sleeve may be eliminated and theentire wheel be made of only resilient material as shown in FIG. 2.

As resilient material for both the annular resilient part 17 and theresilient webs 19, it may advantageously be used solid polyurethanewhich may be cast or molded. Plastic or the like material may also beused.

This type of driving wheel is of low cost and is used for light dutyvehicles such as garden tractors, light or recreational type vehicles,like all terrain vehicles.

FIG. 4 shows a wheel 1 made of a metal sleeve 21, over which is rigidlysecured an annularly shaped resilient part 25. Spring blades or webs 23are rigidly secured to the annular part 25 and radially projecttherefrom. The annular part 25 may be cast or molded in place and blades23 imprisoned therein.

For the resilient material, it may be used solid polyurethane or-plasticor the like.

This type of drving wheel is designated for average duty vehicles, suchas farm tractors.

FIG. shows a wheel 1' made of a metal sleeve 27, surrounded byindependent spring blades or webs 29 radially projecting therefrom andwhich are wedged in place by metal wedges 31. The wedges 31 are pressedin and held in place by cap screws 33.

This type of wheel 1 is designated for heavy duty vehicles, such asheavy tractors, earth moving machinery, graders, lumbering machinery.

In all of these types of driving wheels the thickness of each web is inrelation to the average torque to be transmitted from the motor to theperiphery of the driven wheels 5.

The outside diameter of a driving wheel 1 is also in relation to theoutside diameter of the driven wheels and the multiplication of thrustrequired at the periphery of the driven wheels.

' By outside diameter of a driving wheel it is meant the diametermeasured from tip to tip of two diametrically opposite webs.

As shown in the figures, the metal sleeve 15, 21 or 27 is provided witha spline 16 or splines for the: purpose of rigidly securing the wheel atthe end of the live axle The mode of operation of this differential typedriving wheels system will now be explained with reference to FIGS. 1and 2.

in the straight forward movement of the vehicle, when the powergenerated by motor 9 is transmitted to live axle 3 and therefore to thewebbed driving wheels 1, a torque is developed at the ends of the axle3, which torque is evenly distributed at the free ends or tips of thewebs composing the'driving wheels 1.

As above-mentioned and clearly shown in FIG. 2, each driving wheel I isin constant frictional engagement with a pair of driven wheels 5. Thisfrictional engagement is made possible through a predetermined number ofwebs. The torque existing at the tip of each web which is in contactwith the periphery of driven wheels 5 is thus transmitted to thesedriven wheels 5. The sum of the torques thus transmitted provides therotation of the driven wheels 5 and therefore the moving or propellingof the vehicle. As clearly shown in FIG. 2, when the driving wheels 1rotate in the direction of arrow A, each driven wheel 5 rotates in thedirection of arrows B and C, respectively, and the vehicle advances inthe direction of arrow D (FIG. 1).

Under the influence of the torque existing at the tip of each web, eachweb which comes into contact with the periphery of the driven wheels 5is bent rearward, in the opposite direction of arrow A, in proportion tothe applied torque. This bending of the webs will of course varyaccording to continuously varying factors, such as the condition of theroad (holes and mounds), the pressure or the diameter of each drivenwheel etc., but the moving or propelling action of the driving wheelswill not be effected.

The webs of the driving wheels are made of such a material and are sodimensioned as to permit the bending of the webs, but yet to provide thenecessary strength for transmitting the propelling power of the motor 9to the driven wheels 5.

For the reverse movement the same principle as above-explained appliesbut in the reverse direction.

When negotiated curves this arrangement of drive wheels 1 and-drivenwheels 5 acts as a differential system as will be explained hereinbelow.

in fact, when negotiated curves the interior pair of driven wheels 5covers a lesser distance on the ground than the centerline of thevehicle which we will take as a reference line. To cover a lesserdistance, these interior wheels must rotate less than the rotation theywill have when moving in the straight forward direction or in otherwords less than the rotation of two imaginary wheels placed on thecenterline. On the other hand, the rotation of axle 3 and therefore therotation of both driving wheels 1 is preset from the beginning and isalways constant. But, due to the fact that there is a frictionalengagement between driving wheels 1 and driven wheels 5, the drivingwheels 1 corresponding to the interior driven wheels 5 will have thetendency to follow the reduced rotation of the interior driven wheels 5and therefore will rotate less than their preset speed. This differenceof the speed of rotation between the interior driving wheels 1 and theinterior driven wheels will be absorbed by the resilient webs of theinterior driving wheels 1 which will bend more than they would have bentwhen the vehicle moves in a straightt forward direction. Thus, curveswill be negotiating smoothly and without any difficulties.

The resiliency of the material forming the webs is chosen in such a wayas to provide a safe extra bending of the webs when negotiating curves.

Of course, when negotiating curves, the exterior pair of driven wheels 5will cover, on the ground, a longer distance than the centerline, and bythe same reasoning as above, it is apparent that the webs of theexterior driving wheel 1, will bend less, than their ordinary bendingduring the advance of the vehicle in straight forward direction.

In a further embodiment, where there are provided two pairs of drivenwheels at each side of the vehicle, it will be necessary two live axleswith two driving wheels fixed at the ends of each of them, but the sameprinciple as above-explained will apply. With such double live axles 3and four driving wheels 1, the power of the vehicle will be increased.

Another embodiment would be the possibility of applying the principledescribed in this application to all terrain vehicles which use fordirection or steering the vehicle the principle of varying the speed ofthe wheels on one side in relation to the speed of the wheels on theother side. Then, the principle of one live axle would be retained, butthe live axle would be split on the centerline of the vehicle, makingeach part independent and permitting independent control of the drivenwheels on one side in relation to the other side.

I claim:

1. Differential type driving wheels system for driving self-propelledvehicles such as all terrain vehicles or the like, said differentialsystem comprising:

a single power driven axle rotatably mounted on the body of the vehicle;

a driving wheel fixedly secured on each end of said axle, said axleextending between a pair of driven wheels disposed ateach side of thevehicle with said driving wheels in frictional engagement therewith;

said driving wheels comprising radially projecting circumferentiallybendable resilient webs, said webs having a predetermined substantialradial length and strength and being in constant frictional engagementwith said driven wheels;

said frictional engagement providing the propelling force for thevehicle and independent bending of said webs permitting differentialmovement of the driven wheels when the vehicle is negotiating curveswhile still providing frictional drive thereto. 2. A systemaccording toclaim 1, wherein each of said driving wheels comprises:

a metal sleeve; an annular resilient part rigidly secured around saidsleeve; 7

said bendable webs being fixedly secured around said annular resilientpart and radially projecting therefrom.

3. A system according to claim 1, wherein each of said driving wheelscomprises:

a sleeve made of a resilient material,

said bendable webs being fixedly secured around said resilient sleeveand radially projecting therefrom.

4. A system according to claim 3, wherein said resilient sleeve and saidbendable webs form an integral part and are made of cast or molded solidpolyurethane.

5. A system according to claim 2, wherein said annular resilient partsecured around said metal sleeve, and said bendable webs are made ofcast or molded solid polyurethane.

6. A system according to claim 2, wherein said annular resilient partsecured around said metal sleeve, and said bendable webs are made ofplastic.

7. A system according to claim 3, wherein said resilient sleeve and saidbendable webs are made of plastic.

8. Differential type driving wheels system for driving self-propelledvehicles such as all terrain vehicles or the like, said differentialsystem comprising:

a single power driven axle rotatably mounted on the body of the vehicle;

a driving wheel fixedly secured on each end of said axle, said axleextending between a pair of driven wheels disposed at each side of thevehicle with said driving wheels in frictional engagement therewith;said driving wheels comprising a metal sleeve and an annular resilientpart rigidly secured around said sleeve, circumferentially bendablespring blades or webs being rigidly secured to said annular part andradially projecting therefrom, said blades having a predetermined lengthand strength and being in constant frictional engagement with saiddriven wheels, I

said frictional engagement providing the propelling force for thevehicle and independent bending of said spring blades permittingdifferential movement of the driven wheels when the vehicle isnegotiating curves while still'providing frictional drive thereto.

9. Differential type driving wheels system for driving self-propelledvehicles such as all terrain vehicles or the like wherein conventionaldifferential means are eliminated, said system comprising:

an axle actuatedby a motor and rotatably secured to the body of thevehicle; driving wheels, each wheel being connected at one end of saidaxle and being mounted between a pair of said driven wheels disposed ateach side of the vehicle,

said driving wheels comprising a metal sleeve and bendable spring bladesor webs, said blades radially projecting from said sleeve and beingrigidly wedged around said sleeve by means of wedges which are pressedbetween two adjacent blades and are held in place by screws, said bladeshaving a predetermined length and strength and being in permanentfrictional engagement with said driven wheels,

said frictional engagement providing the bending of said baldes in sucha way as to provide the propelling of the vehicle and also thedifferential movement of the driven wheels when the vehicle isnegotiating curves.

(2)3? UNITED STATES PATENT; OFFICE R FICATE OF CORRECTION Patent No. ,7,420 Dated January 29, 1974 Inventorfit) JEAN PAUL LACROIX It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

IN THE SPECIFICATION:

Col. 4, line 45, "negotiated" should read --negotiating-- Col. 4, line29, "negotiating" should read ---negotiated-- I Signed and sealed this2nd day of July 1974 .(SEAL) Attest:

EDWARD M. FLETCHER,JR. C.MARSHALL DANN I Attestlng Officer Commissionerof Patents

1. Differential type driving wheels system for driving selfpropelledvehicles such as all terrain vehicles or the like, said differentialsystem comprising: a single power driven axle rotatably mounted on thebody of the vehicle; a driving wheel fixedly secured on each end of saidaxle, said axle extending between a pair of driven wheels disposed ateach side of the vehicle with said driving wheels in frictionalengagement therewith; said driving wheels comprising radially projectingcircumferentially bendable resilient webs, said webs having apredetermined substantial radial length and strength and being inconstant frictional engagement with said driven wheels; said frictionalengagement providing the propelling force for the vehicle andindependent bending of said webs permitting differential movement of thedriven wheels when the vehicle is negotiating curves while stillproviding frictional drive thereto.
 2. A system according to claim 1,wherein each of said driving wheels comprises: a metal sleeve; anannular resilient part rigidly secured around said sleeve; said bendablewebs being fixedly secured around said annular resilient part andradially projecting therefrom.
 3. A system according to claim 1, whereineach of said driving wheels comprises: a sleeve made of a resilientmaterial, said bendable webs being fixedly secured around said resilientsleeve and radially projecting therefrom.
 4. A system according to claim3, wherein said resilient sleeve and said bendable webs form an integralpart and are made of cast or molded solid polyurethane.
 5. A systemaccording to claim 2, wherein said annular resilient part secured aroundsaid metal sleeve, and said bendable webs are made of cast or moldedsolid polyurethane.
 6. A system according to claim 2, wherein saidannular resilient part secured around said metal sleeve, and saidbendable webs are made of plastIc.
 7. A system according to claim 3,wherein said resilient sleeve and said bendable webs are made ofplastic.
 8. Differential type driving wheels system for drivingself-propelled vehicles such as all terrain vehicles or the like, saiddifferential system comprising: a single power driven axle rotatablymounted on the body of the vehicle; a driving wheel fixedly secured oneach end of said axle, said axle extending between a pair of drivenwheels disposed at each side of the vehicle with said driving wheels infrictional engagement therewith; said driving wheels comprising a metalsleeve and an annular resilient part rigidly secured around said sleeve,circumferentially bendable spring blades or webs being rigidly securedto said annular part and radially projecting therefrom, said bladeshaving a predetermined length and strength and being in constantfrictional engagement with said driven wheels, said frictionalengagement providing the propelling force for the vehicle andindependent bending of said spring blades permitting differentialmovement of the driven wheels when the vehicle is negotiating curveswhile still providing frictional drive thereto.
 9. Differential typedriving wheels system for driving self-propelled vehicles such as allterrain vehicles or the like wherein conventional differential means areeliminated, said system comprising: an axle actuated by a motor androtatably secured to the body of the vehicle; driving wheels, each wheelbeing connected at one end of said axle and being mounted between a pairof said driven wheels disposed at each side of the vehicle, said drivingwheels comprising a metal sleeve and bendable spring blades or webs,said blades radially projecting from said sleeve and being rigidlywedged around said sleeve by means of wedges which are pressed betweentwo adjacent blades and are held in place by screws, said blades havinga predetermined length and strength and being in permanent frictionalengagement with said driven wheels, said frictional engagement providingthe bending of said baldes in such a way as to provide the propelling ofthe vehicle and also the differential movement of the driven wheels whenthe vehicle is negotiating curves.